The current research on the free-flow speed of motorcycle on bridges is rather lacking. Therefore, this study is aimed at the five important bridges between Taipei City and New Taipei City, and conducts field investigation and analysis of the free-flow speed characteristics of the motorcycles on the bridges.
This study uses the travel time survey method to collect motorcycle travel speed data. Firstly, it selected a straight and flat section on the bridge. Secondly, it set up two time-synchronized video recorders to record the time required for the motorcycle pass the section. Thirdly, it used the section distance divided the travel time to obtain the motorcycle sectional average speed data. It is suggested
to use the headway for more than 3 seconds to define a motorcycle travel on free-flow situation or not by field data analysis. The average motorcycle speed with a headway more than 3 seconds begins to stabilize, and there is no significant different with other longer headway groups. And, all motorcycle free-flow speeds are distributed as normal distribution by K-S test and Q-Q plot.
The average motorcycle free-flow speeds on the five bridges are as high as 52.6~56.8 km/h with a speed limit of 40 km/h, and there are as many as 85.1%~93.0% motorcycles speeding. The study also found that the motorcycle free-flow speed on the bridge is positively correlated with the lane width, and the free-flow speed increases with the increase of the lane width. The research results of this study can further understand the motorcycle driving characteristics of Taiwan's bridge and the future as a reference for sectional average speed enforcement.